Particle engines are used a lot in 3D applications. Basically they can be defined by a large array of certain variables. X, Y, and Z coordinates are required. Increment variables for the X, Y, Z variables are also required.
Here's a simple example of the particle engine array:
#define MAX_PARTICLES 100 // Number of particles typedef struct // Create A Structure For Particle { float life; // Particle Life float fade; // Fade Speed float x; // X Position float y; // Y Position float z; // Z Position float xi; // X Direction float yi; // Y Direction float zi; // Z Direction } particles; // Particles Structure particles particle[MAX_PARTICLES]; // Particle Array
Other variables could be put into the array easily, such as Red, Green, and Blue variables.
To initialize the particles, use this code:
int loop; float V,Angle; for (loop=0; loop<MAX_PARTICLES; loop++) // Initializes All The Textures { particle[loop].life=1.0f; // Give All The Particles Full Life particle[loop].fade=float(rand()%100)/1000.0f+0.05f; // Random Fade Speed
V = float(rand()%25); // Speed of the particle Angle = float(rand()%360); // Angle of the particle
particle[loop].x = 0; // Set X position particle[loop].y = 0; // Set Y position particle[loop].z = 0; // Set Z position
particle[loop].xi = sin(Angle) * V; // Set X velocity particle[loop].yi = cos(Angle) * V; // Set Y velocity particle[loop].zi = float(((rand()%10)-5)/10) * V; // Set Z velocity }
Finally, to draw the particles and animate them you will probably want to find a texture to use. I like to use a blurry texture that blends well. Use this code:
for (loop=0; loop<MAX_PARTICLES; loop++) // Loop Through All The Particles {
float x=particle[loop].x; // Grab Our Particle X Position float y=particle[loop].y; // Grab Our Particle Y Position float z=particle[loop].z; // Grab Our Particle Z Position
// Draw The Particle Using Our RGB Values, Fade The Particle Based On It's Life glColor4f(.5f,.5f,1.f,particle[loop].life);
glBegin(GL_TRIANGLE_STRIP); // Build Quad From A Triangle Strip glTexCoord2f(1,1); glVertex3f(x+0.2f,y+0.2f,z); // Top Right glTexCoord2f(0,1); glVertex3f(x-0.2f,y+0.2f,z); // Bottom Right glTexCoord2f(1,0); glVertex3f(x+0.2f,y-0.2f,z); // Top Left glTexCoord2f(0,0); glVertex3f(x-0.2f,y-0.2f,z); // Bottom Left glEnd(); // Done Building Triangle Strip
particle[loop].x+=particle[loop].xi/250; // Move On The X Axis By X Speed particle[loop].y+=particle[loop].yi/250; // Move On The Y Axis By Y Speed particle[loop].z+=particle[loop].zi/250; // Move On The Z Axis By Z Speed
// Slow down the particles particle[loop].xi*=.975; particle[loop].yi*=.975; particle[loop].zi*=.975;
particle[loop].life-=particle[loop].fade; // Reduce Particles Life By 'Fade'
if (particle[loop].life<0.05f) // If Particle Is Burned Out { particle[loop].life=1.0f; // Give It New Life particle[loop].fade=float(rand()%100)/7500 + 0.0075f; // Random Fade Value particle[loop].x= 0; // Center On X Axis particle[loop].y= 0; // Center On Y Axis particle[loop].z= 0; // Center On Z Axis V = (float((rand()%9))+1); Angle = float(rand()%360);
That's pretty much it. I know that you'll probably have questions even after looking at this. So I'm giving you a little example program so you can experiment with the engine. Download it here. I hope this helps you out. =)
